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Topics To Cover:
• Psilocybin containing “magic mushrooms”
• Amanita muscaria / Fly Agaric mushrooms
– History/tradition/culture
– Pharmacology
“Magic Mushrooms”
• Multiple species of the Psilocybe genus– 240 psychoactive mushrooms, 170 are
psilocybin-containing
– 60 Psilocybe spp. growing naturally in the US, 25 are hallucinogenic
Traditional Use
• Used by Mesoamerican natives
• Religious communion, divination, and healing
• Used for thousands of years until Spanish invaded
• 1955: Wasson first westerner to take mushrooms
Effects
• Mood lift, euphoria, giggling, laughter, giddiness, increased flow of ideas/deep thinking, things become more interesting/colourful
• General change in consciousness, feeling more emotionally sensitive, time dilation, photosensitivity, sleepiness, pupil dilation, buzzing/energy in periphery
• Intense fear, headache as effects subside, nausea, GIT discomfort, anxiety, dizziness, confusion, lightheadedness/syncope
Pharmacology
• Active compounds: Psilocybin and Psilocin –
tryptamines
• Only Psilocin is biologically active
Psilocin
• 5HT2A, 5HT2C and 5HT1A agonist
• Hallucinatory effects due to 5-HT2A binding in brain
• No effects on DA systems
• Only affects NA systems in high doses
• Extent of blue/black bruising is indicative of potency
Clinical Implications
• No recognised medical use
• BUT – used as experimental treatment for a variety of disorders
Cluster headaches
Easing psychological suffering
associated with cancer
Amanita muscaria
• Grows throughout the northern hemesphere
• Poisonous when fresh
• Completely legal
Amanita muscaria
• Appear (alongside Psilocybe spp.) in Algerian art from 3500 BC
• Appearances in paintings from renaissance, more prominent in Victorian era
• Typically associated with fairies, elves, “little people”
• Christmas
• Alice in Wonderland
Traditional Use
• Use was widespread, but in Siberia in particular
• Siberian shamans would use it as an alternative method to enter a trance state
• Eastern Siberian shamans and laypeople used it religiously and recreationally
Effects
• Euphoria, analgesia, relaxation, trance/dreamlike state, synaesthesia, clarity of thought, social feelings, increased sexual feelings, seeing little people
• Sedative (but some people become energetic), changes in body perception (motor skills, size, proprioception), pupil dilation, blurred vision, watery eyes, runny nose.
• Nausea, GIT discomfort, muscle twitching, increased salivation and perspiration, powerful dissociation and delirium at high doses
Pharmacology
• Active compounds: Ibotenic acid and Muscimol– Ibotenic acid is a neurotoxin
• Found use as a brain lesioning agent
• Responsible for toxic delirium when fresh mushrooms are eaten
– Decarboxylates into Muscimol during drying process
Muscimol
• Selective GABA-A agonist/GABA-C partial agonist
– Binds to GABA site, not an allosteric
modulator
• Alters neuronal activity in many brain regions
– Cerebral cortex, hippocampus, cerebellum
• Passes through the body unaltered
Muscimol Bits & Pieces
• Alcohol withdrawal can lead to hallucinations of
“little people”
– Alcohol also acts on GABA systems
– Could these symptoms be related?
• Siberian tribes used to drink their shaman’s
urine
– We now know muscimol passes through the body unchanged � presence in urine
– Who decided to try this first?!
• Negligable muscarinic effects